A method and application of nanoceramic particle dispersion reinforced aluminum matrix alloy friction stir solid additive manufacturing

Abstract

A kind of nano ceramic particle dispersion reinforced aluminum matrix alloy friction stir solid additive manufacturing method and application.The present application belongs to the field of metal solid additive manufacturing.The purpose of the present application is to solve the technical problems of existing ceramic particle reinforced aluminum matrix composite forming process, such as easy agglomeration of ceramic particles, poor performance in vertical processing direction of composite material and cutting difficulty. The method of the present application: according to the atomic ratio of ceramic particles, mixed salt is added to aluminum melt, ceramic particles are generated in situ after stirring for a certain time, then alloy raw materials are added according to the atomic ratio of aluminum matrix alloy for melting, and then casting is carried out to obtain nano ceramic particle reinforced aluminum matrix alloy; the nano ceramic particle reinforced aluminum matrix alloy is used as a self-loss stir head to perform friction stir solid additive manufacturing on the surface of metal base material to obtain nano ceramic particle dispersion reinforced aluminum matrix alloy. The method of the present application is used for forming nano ceramic particle dispersion reinforced 2 series, 3 series, 4 series, 5 series, 6 series and 7 series aluminum alloy.

Description

Technical Field

[0001] This invention belongs to the field of solid metal additive manufacturing, specifically relating to a method and application of solid additive manufacturing of aluminum-based alloys using friction stir with nano-ceramic particle dispersion reinforcement. Background Technology

[0002] Ceramic particle-reinforced aluminum matrix composites possess advantages such as high specific strength, high elastic modulus, good thermal stability, and excellent wear resistance, making them suitable for manufacturing key components in aerospace and automotive industries. The preparation of ceramic particle-reinforced aluminum matrix composites typically employs methods such as powder metallurgy and melt stirring casting. Compared to external particle preparation techniques, in-situ reaction-based particle-reinforced aluminum matrix composites offer the following advantages: 1) Better wettability between ceramic particles and the aluminum matrix, a cleaner interface, and higher interfacial bonding strength; 2) Ceramic particles nucleate and grow within the matrix, exhibiting higher thermodynamic stability and making them more suitable for high-temperature service environments; 3) Smaller and more uniformly distributed ceramic reinforcing phase particles, resulting in a more significant reinforcing effect. For example, in-situ self-generated TiB2 / 7075Al composites exhibit superior modulus, strength, hardness, and high-temperature creep properties compared to non-in-situ self-generated TiB2 / 7075Al composites. In-situ self-generated aluminum matrix composites have already been applied in key structural components of some major equipment in my country and are one of the ideal materials for lightweight design of aerospace structural components.

[0003] However, in-situ self-generated aluminum matrix composites still face a series of technological challenges in material preparation, processing, and component forming. Industrial applications are still limited, and a corresponding materials industry has not yet been formed. On the one hand, in-situ synthesized nanoparticle-reinforced aluminum matrix composites often exhibit particle agglomeration. Although subsequent extrusion and rolling processes can eliminate solidification defects to some extent, they cannot solve the problem of ceramic particle agglomeration. Agglomerated ceramic particles easily become crack sources during service, leading to composite failure. On the other hand, subsequent extrusion and rolling processes can refine grains and improve the microstructure of the composite. However, the strip-like structure formed after extrusion or rolling results in significant anisotropy of the material. It exhibits high strength and plasticity along the processing direction, but its overall performance is often poor in the direction perpendicular to the processing direction, thus limiting its application in some critical structural components. Furthermore, the addition of ceramic particles increases the strength and wear resistance of the composite, making the forming and machining of the composite increasingly difficult and costly, especially for the forming of large structural components, which presents a greater challenge. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of easy agglomeration of ceramic particles and poor performance of composite materials in the vertical processing direction and difficult cutting in the existing molding process of ceramic particle reinforced aluminum matrix composites. Therefore, this invention provides a method and application for solid additive manufacturing of aluminum matrix alloys by friction stir with nano-ceramic particle dispersion reinforcement.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] One objective of this invention is to provide a method for solid additive manufacturing of aluminum-based alloys using friction stir, which is reinforced by the dispersion of nano-ceramic particles. The method comprises the following steps:

[0007] S1: Add mixed salt to aluminum melt according to the atomic ratio of ceramic particles, stir for a certain time to generate ceramic particles in situ, then add alloy raw materials according to the atomic ratio of aluminum-based alloy for melting, and then cast to obtain aluminum-based alloy reinforced with nano-ceramic particles.

[0008] S2: Using a self-consuming stirring head, an aluminum-based alloy reinforced with nano-ceramic particles is used to perform friction stir solid additive manufacturing on the surface of a metal substrate to obtain a nano-ceramic particle dispersion reinforced aluminum-based alloy.

[0009] Preferably, the ceramic particles in S1 are TiB2, TiC, or ZrB2.

[0010] Preferably, the mixed salt in S1 is any two of potassium fluorotitanate (K2TiF6), potassium fluoroborate (KBF4), and K2ZrF6.

[0011] Preferably, the ceramic particle content in the aluminum melt in S1 is 0.5-15.0 wt.%.

[0012] Preferably, the stirring speed in S1 is 500-700 rpm and the stirring time is 10-20 min.

[0013] Preferably, the metal substrate in S2 is pure aluminum, aluminum alloy, magnesium alloy or aluminum-based composite material.

[0014] Preferably, the self-consuming stirring head in S2 rotates at a speed of 300-1500 rpm and the feed speed is 2-100 mm / min.

[0015] The second objective of this invention is to provide a nano-ceramic particle dispersion-reinforced aluminum-based alloy prepared by the above method, wherein the grain size of the nano-ceramic particle dispersion-reinforced aluminum-based alloy is 300nm-5μm, and the nano-ceramic particles are uniformly dispersed without agglomeration.

[0016] Preferably, the size of the nano-ceramic particles is 50nm-3μm.

[0017] The third objective of this invention is to provide an application of the above method in nano-ceramic particle-reinforced aluminum and its alloy materials, wherein the aluminum alloys include 2-series, 3-series, 4-series, 5-series, 6-series and 7-series aluminum alloys.

[0018] The significant advantages of this invention compared to existing technologies are:

[0019] The method of this invention applies axial pressure and high-speed rotation of a consumable agitator, causing the aluminum-based composite material to undergo intense plastic deformation upon interaction with the substrate. This achieves metallurgical bonding on the aluminum alloy or magnesium alloy substrate, allowing for layer-by-layer agitation deposition to prepare aluminum-based composite coatings or thick aluminum-based composite components. The intense plastic deformation of the aluminum-based composite material results in the dispersion of nano / submicron ceramic particles within the aluminum matrix, solving the problem of ceramic particle agglomeration or localized segregation in the aluminum matrix. Simultaneously, it enables control over the ultrafine grain structure of the aluminum matrix. The deposition path can be precisely controlled by a robotic arm according to a planned path. Combined with subtractive machining processes, this allows for the low-cost and rapid manufacturing of large, high-performance aluminum-based composite components. Specific advantages include:

[0020] (1) The present invention uses an in-situ self-generated method to prepare aluminum matrix composite material reinforced with ceramic particles. Compared with the conventional method of adding external ceramic reinforcing particles, it can achieve the diffuse distribution of nano- and submicron ceramic particle reinforcing phases in the aluminum matrix, and the ceramic particle interface and the aluminum matrix interface are well bonded and the interface is clean.

[0021] (2) The present invention uses the friction stir solid additive manufacturing method to prepare aluminum-based composite materials. Compared with conventional laser or electron beam additive manufacturing, the heat input is low, which can avoid problems such as oxidation, phase transformation and grain growth. The friction stir additive manufacturing technology can further refine the grains, realize the uniform ultrafine grain structure of the aluminum matrix, and solve the problem of local agglomeration of ceramic particles, thus improving casting defects.

[0022] (3) The aluminum-based composite material prepared by the friction stir additive manufacturing technology used in this invention has excellent comprehensive performance. It can solve the problem that the composite material prepared by other plastic forming processes and high-energy beam additive manufacturing processes has obvious anisotropy. At the same time, by controlling the microstructure at multiple scales, it can solve the problem that the aluminum-based composite material reinforced by ceramic particles is difficult to achieve both strength and plasticity.

[0023] (4) The friction stir additive manufacturing technology used in this invention has advantages such as high manufacturing efficiency and low cost. It is suitable for rapid prototyping of large structural parts, especially for the manufacturing of high-strength aluminum alloy components (2xxx, 6xxx and 7xxx aluminum alloys) reinforced with ceramic particles. Attached Figure Description

[0024] Figure 1This is a schematic diagram of the process for the solid additive manufacturing method of aluminum-based alloy with nano-ceramic particle dispersion reinforcement according to the present invention; in the figure: 1-electric furnace body, 2-crucible, 3-aluminum alloy melt, 4-slag, 5-blade stirrer, 6-mold, 7-cast aluminum-based composite material, 8-self-consumable stirring head, 9-hollow rotating tool, 10-metal substrate, 11-nano-ceramic particle dispersion reinforcement aluminum-based alloy.

[0025] Figure 2 Metallographic image of the aluminum-based alloy with nano-ceramic particle dispersion reinforcement obtained in Example 1;

[0026] Figure 3 The image shows the grain size distribution of the nano-ceramic particle dispersion-reinforced aluminum matrix composite material prepared in Example 1.

[0027] Figure 4 The tensile properties of the nano-ceramic particle dispersion-reinforced aluminum matrix composite material prepared in Example 1 are shown along the deposition direction. Detailed Implementation

[0028] One specific embodiment of the present invention provides a method for solid additive manufacturing of aluminum-based alloys by friction stirring with nano-ceramic particle dispersion reinforcement, the method comprising the following steps:

[0029] S1: Add a mixed salt to the aluminum melt according to the atomic ratio of ceramic particles, stir for a certain time to generate ceramic particles in situ, then add alloy raw materials according to the atomic ratio of aluminum-based alloys for melting, and then cast to obtain an aluminum-based alloy reinforced with nano-ceramic particles; wherein, the ceramic particles are TiB2, TiC, and ZrB2; the mixed salt is any two of potassium fluorotitanate (K2TiF6), potassium fluoroborate (KBF4), and K2ZrF6; the content of ceramic particles in the aluminum melt is 0.5-15.0 wt.%; the stirring speed is 500-700 rpm, and the time is 10-20 min;

[0030] S2: Aluminum-based alloy reinforced with nano-ceramic particles is used as a self-consuming stirring head to perform friction stir solid additive manufacturing on the surface of a metal substrate to obtain a nano-ceramic particle dispersion reinforced aluminum-based alloy; wherein the metal substrate is pure aluminum, aluminum alloy, magnesium alloy or aluminum-based composite material; the rotation speed of the self-consuming stirring head is 300-1500 rpm and the feed speed is 2-100 mm / min.

[0031] In a specific embodiment of the present invention, the first step achieves the dispersed distribution of nano / submicron ceramic particles in the aluminum matrix through in-situ self-generated reaction, while ensuring good interfacial bonding between the ceramic reinforcing phase particles and the aluminum alloy matrix. The amount of nano / submicron ceramic particles added is 0.5 wt.%-15.0 wt.%. If the amount of ceramic particles added is too large, local agglomeration or segregation of the ceramic reinforcing phase may occur. After the second step of stirring and friction solid deposition, the ceramic particles can be further dispersed, making them more dispersed in the aluminum alloy matrix. Intense plastic deformation causes recrystallization of the aluminum matrix, thereby refining the grains and eliminating defects.

[0032] In a specific embodiment of the present invention, the additive material (self-consuming stirring head) can be processed into a square or rod shape, and its size can vary depending on the equipment and specific process conditions. The substrate can be pure aluminum or lightweight metal materials such as aluminum alloy, magnesium alloy, or aluminum-based composite materials, and its shape and size are not limited. The thickness of each deposition layer, the deposition shape of the component, and its size can vary depending on the specific process conditions.

[0033] In a specific embodiment of the present invention, the obtained nano-ceramic particle dispersion-reinforced aluminum-based alloy has a grain size of 300nm-5μm, and the nano-ceramic particles are uniformly dispersed without agglomeration, with a particle size of 50nm-3μm.

[0034] Another specific embodiment of the present invention is to provide an application of the above method in nano-ceramic particle-reinforced aluminum and its alloy materials, wherein the aluminum alloy includes 2-series, 3-series, 4-series, 5-series, 6-series and 7-series aluminum alloys.

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0037] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used in the following embodiments, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such a composition, step, method, article, or apparatus.

[0038] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range. In this specification and claims, range definitions may be combined and / or interchanged, unless otherwise stated, these ranges include all subranges contained therein.

[0039] The indefinite articles “a” and “an” preceding an element or component of this invention do not impose any limitation on the quantity (i.e., number of times) of the element or component. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0040] In this invention, "an embodiment" or "embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0041] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0042] Example 1 Figure 1 An embodiment of the present invention is given, and the specific operation includes the following steps:

[0043] (1) First, pure aluminum is placed in a graphite crucible in an electric furnace 1 and heated to 900℃. After the aluminum is completely melted, 99.0% pure industrial-grade potassium fluorotitanate (K2TiF6) and potassium fluoroborate (KBF4) are added to the aluminum melt 3 in an atomic ratio of Ti:B = 1:2, and 600g of calcium fluoride is added as a flux. The mixture is mechanically stirred at 600rpm for 15min using a blade stirrer 5. Then, the aluminum melt is batched according to the 7075Al alloy, and Al-Cu, Al-Zn, and Mg-Zn master alloys are added for smelting. After the reaction is completed, the reaction byproducts 4 are removed, and the melt is poured into a metal mold 6 to obtain a φ300mm×200mm as-cast 7wt.% TiB2 / Al-Zn-Mg-Cu composite rod 7. The chemical composition of the as-cast composite material was determined, and the results showed that the contents of Zn, Mg and Cu were 5.2 wt.%, 1.5 wt.% and 2.4 wt.% respectively, and the content of TiB2 was 7 wt.%, which met the requirements of the alloy composition range.

[0044] (2) The above-mentioned rod 7 is machined into a small cylindrical rod 8 with a diameter of φ14mm × 200mm, and used as the material for friction stir additive manufacturing (self-consuming stirring head). It is placed in a hollow rotary tool 9 and connected to the friction stir welding equipment by bolts. 7075 aluminum alloy is selected as the substrate 10, with a substrate thickness of 15mm, a substrate width of 60mm, and a substrate length of 300mm. The cleaned substrate 10 is fixed on the flat base using a tooling fixture to ensure that the substrate 10 does not slip during the friction stir additive manufacturing process. The friction stir additive manufacturing equipment is started, and the feed speed and rotation speed of the cylindrical rod 8 are adjusted; the rotation speed of the rod 8 is 800r / min, and the feed speed of the rod 8 is 500mm / min. When the rod 8 contacts the substrate 10, the rod 8 moves along the set trajectory and speed, and additive manufacturing begins. By reciprocating the stirring head and continuously changing the rod, aluminum-based composite material is deposited layer by layer to form deposit 11, namely, aluminum-based alloy with nano-ceramic particle dispersion reinforcement.

[0045] Figure 2 The image shows the metallographic diagram of the nano-ceramic particle dispersion-reinforced aluminum-based alloy obtained in Example 1. As can be seen from the image, TiB2 particles are dispersed in the dense aluminum alloy matrix, with particle sizes ranging from 500 nm to 2 μm and a volume fraction of 4.2 vol.%.

[0046] Figure 3 The image shows the grain size distribution of the aluminum-based composite material prepared in Example 1. As can be seen from the image, the grain size ranges from 300 nm to 3 μm, with an average grain size of 1.6 μm.

[0047] Figure 4The tensile properties of the aluminum-based composite material prepared in Example 1 along the deposition direction were as follows: the tensile strength in the deposited state reached 500 MPa and the elongation was 12.0%. After T6 heat treatment, the tensile strength reached 580 MPa and the elongation was 8.0%.

[0048] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for solid-state additive manufacturing of aluminum-based alloys using friction stir, characterized in that, Follow these steps: S1: Add mixed salt to aluminum melt according to the atomic ratio of ceramic particles, stir for a certain time to generate ceramic particles in situ, then add alloy raw materials according to the atomic ratio of aluminum-based alloy for melting, and then cast to obtain aluminum-based alloy reinforced with nano-ceramic particles. S2: Aluminum-based alloy reinforced with nano-ceramic particles is used as a self-consuming stirring head to perform friction stir solid additive manufacturing on the surface of a metal substrate to obtain a nano-ceramic particle dispersion reinforced aluminum-based alloy. The self-consuming stirring head in S2 rotates at a speed of 300-1500 rpm, and the feed rate is 2-100 mm / min.

2. The method according to claim 1, characterized in that, The ceramic particles in S1 are TiB2, TiC, and ZrB2.

3. The method according to claim 1, characterized in that, The mixed salt in S1 is any two of K2TiF6, KBF4, and K2ZrF6.

4. The method according to claim 1, characterized in that, The ceramic particle content in the aluminum melt in S1 is 0.5-15.0 wt.%.

5. The method according to claim 1, characterized in that, In S1, the stirring speed is 500-700 rpm and the time is 10-20 min.

6. The method according to claim 1, characterized in that, The metal substrate in S2 is pure aluminum, aluminum alloy, magnesium alloy or aluminum-based composite material.

7. The nano-ceramic particle dispersion-reinforced aluminum-based alloy prepared by the method according to any one of claims 1-6, characterized in that, The alloy grain size is 300 nm-5 μm, and the nano-ceramic particles are uniformly dispersed without agglomeration.

8. The nano-ceramic particle dispersion reinforced aluminum-based alloy according to claim 7, characterized in that, The nano-ceramic particles have a size of 50 nm to 3 μm.

9. The application of the method according to any one of claims 1-6 in nano-ceramic particle-reinforced aluminum and its alloy materials, characterized in that, Aluminum alloys include 2-series, 3-series, 4-series, 5-series, 6-series, and 7-series aluminum alloys.

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